function check(){
    var s13=document.getElementById("s13");
    var s14=document.getElementById("s14");
    var money=350*flag;
    s13.innerHTML="￥"+money+"元(含税费)"
    s14.innerHTML=flag+"人"
   var t2= document.getElementById("t2");
    if(t2.value ==""){
        alert("联系人不能为空，请重新输入");
    }
    var t3= document.getElementById("t3");
    var check=new RegExp("^1[0-9]{10}$");
    if(!check.test(t3.value)){
            alert("手机号码输入错误，请重新输入");
}
}